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Radio circuit diagrams electronics projects

Radio circuit diagrams electronics projects for radio transmitter, radio receiver circuit, rf amplifiers, rf boosters and some other related RF circuits like: fm antenna booster, microwave transmitter and wireless modules.

ADF7242 low power transceiver circuit

This low power transceiver circuit project is designed using the ADF7242 fully integrated low-cost, short-range, low power transceiver designed for operation in the global 2.4 GHz ISM band.
The receive path of the ADF7242 low power transceiver circuit is based on a zero-IF architecture enabling high blocking and selectivity performance. The transmit path is based on a direct closed loop VCO modulation scheme.
The ADF7242 has a low consumption power that make it suitable for battery powered systems.
The agile frequency synthesizer of the  ADF7242 together with short turnaround times facilitates the implementation of FHSS transmission systems.
The ADF7242 features a flexible dual port RF-interface with support for switched antenna diversity.

The ADF7242 supports IEEE 802.15.4 compliant DSSS-OQPSK modulation with a bitrate of 250 kbps and also supports FSK and GFSK modulation with bitrates from 62.5 kbps to 2 Mbps.
ADF7242 fully supports arbitrary data rates only for FSK mode of operation.
The ADF7242 also has a built in battery monitor features that has a very low power consumption and may be used in parallel with any mode of operation, except SLEEP state. The battery monitor generates a battery alert  interrupt for the MCU when the battery voltage drops below the programmed threshold voltage.

The ADF7242 transceiver is equipped with a 4 wire SPI interface ( SCLK, SO, SI and CSN ).
The ADF7242 transceiver circuit has many features like : programmable data rates and modulation , low power consumption (18 mA (typ.) in receive mode , 22 mA (typ.) in transmit mode (Po = 3 dBm) 1.25μA 32kHz xtal oscillator wake-up mode) , high sensitivity  (97 dBm at 250 kbps (IEEE 802.15.4), 93 dBm at 250 kbps (GFSK) , 84 dBm at 2 Mbps (GFSK) ) , programmable output power, integrated voltage regulator (1.8 V to 3.6 V input voltage range) , zero-IF architecture, digital RSSI measurement , 256 bytes for TX /RX buffer , flexible multiple RF port interface , external PA/LNA support hardware , switched antenna diversity support , wake up timer , integrated PLL loop filter , integrated battery monitor , temperature sensor , integrated RC and 32kHz crystal oscillator , flexible SPI control interface and many others .
ADF7242 low power transceiver circuit diagram and schematic

RF Metal detector schematic circuit

This metal detector schematic circuit is based on a transistor radio as an detector . With the radio tuned to a weak station you must adjust the variable capacitor  C1 until the locator oscillator beats against the received signal . If a metal is detected the inductance of the L1 coil is changed ,  changing the frequency of the locator oscillator’s  , resulting a change in the beat tone radio . The L1 search coil of the metal detector circuit must have  18 turns from a 0.65 mm enameled wire  scrambled on a 4 inch diameter support  .
This metal detector circuit needs to be powered using a 9 volts power supply ( DC) or a 9 volts battery .

The C1 capacitor is a variable capacitor with a value of 365 pF , C2 is a 100pF silver mica capacitor , C3 is a 0.05 uF disc capacitor and the C4 is a 4.7 uF capacitor .
The Q1 transistor can be RCA SK3011 npn transistor or equivalent type  and all resistors need to be ½ watts .

RF Metal detector circuit diagram

TDA1083 AM radio circuit schematic

This radio receiver circuit is based on the TDA1083 radio IC that can be used to build a simple MF band radio . This radio schematic circuit based on the TDA1083 will work in 300kHz – 3MHz frequency range  .
This AM radio circuit is very simple and require few external components  . Using the TDA1083 we can make a AM FM radio receiver but in this diagram is presented just the AM part .
TDA1083 support a wide input voltage range and has a high AM sensitivity  . If you don’t want much audio output power than 0.7W you don’t need to use another audio amplifier stage to increase the audio power because the TDA1083 circuit has a build-in audio amplifier stage  .
As you can see in the circuit diagram  of the Tda1083 the IC contains all needed stages to build a AM FM radio receiver .

If you want to use this circuit you need to make some coils  :
L1 and L2  needs to be placed on the same ferrite support with 10 mm diameters and 100 mm long . The L1 has 80 turns and L2 8 turns ( L2 is placed at 5 mm distance from L1 coil ) .
L3 has coil has 30 turns  on a small piece of ferrite . For all three coils you need to use a 0.2 mm CuEm wire . For this am radio circuit we need a 4.5 volts dc power supply . C1 capacitor mounted in parallel with the L1 coil is a 270 pF variable capacitor .

TDA1083 diagram circuit TDA1083 AM radio receiver circuit


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